<template>
  <div class="containers">
    <div class="canvas" ref="canvas"></div>
    <div id="js-properties-panel" class="panel"></div>
    <ul class="buttons">
      <li>
          <a ref="saveDiagram" href="javascript:" title="保存为bpmn">保存为bpmn</a>
      </li>
      <li>
          <a ref="saveSvg" href="javascript:" title="保存为svg">保存为svg</a>
      </li>
    </ul>
  </div>
</template>

<script>
// 引入相关的依赖
import { newDiagram } from './newDiagram'
import CustomModeler from './customModeler'
import axios from 'axios'
export default {
  name: '',
  props: {
    xmlUrl: {
      type: String,
      default: ''
    }
  },
  components: {},
// 生命周期 - 创建完成（可以访问当前this实例）
  created() {},
// 生命周期 - 载入后, Vue 实例挂载到实际的 DOM 操作完成，一般在该过程进行 Ajax 交互
  mounted() {
    this.init()
  },
  data() {
    return {
      // bpmn建模器
      bpmnModeler: null,
      container: null,
      canvas: null,
      defaultXmlStr: newDiagram
    }
  },
// 方法集合
  methods: {
    async init () {
      this.$nextTick(() => {
        this.initBpmn()
      })
    },
    initBpmn () {
      // 获取到属性ref为“canvas”的dom节点
      const canvas = this.$refs.canvas
      // 建模
      this.bpmnModeler = new CustomModeler({
        container: canvas,
        //添加控制板
        propertiesPanel: {
          parent: '#js-properties-panel'
        },
        additionalModules: []
      })
      this.createNewDiagram()
    },
    async createNewDiagram () {
      const that = this
      let bpmnXmlStr = ''
      if (this.xmlUrl === '') {
          bpmnXmlStr = this.defaultXmlStr
          this.transformCanvas(bpmnXmlStr)
      } else {
          let res = await axios({
              method: 'get',
              timeout: 120000,
              url: that.xmlUrl,
              headers: { 'Content-Type': 'multipart/form-data' }
          })
          console.log(res)
          bpmnXmlStr = res['data']
          this.transformCanvas(bpmnXmlStr)
      }
    },
    transformCanvas(bpmnXmlStr) {
      // 将字符串转换成图显示出来
      this.bpmnModeler.importXML(bpmnXmlStr, (err) => {
        if (err) {
          console.error(err)
        } else {
          this.success()
        }
        // 让图能自适应屏幕
        var canvas = this.bpmnModeler.get('canvas')
        canvas.zoom('fit-viewport')
      })
    },
    success () {
      this.addBpmnListener()
      this.addModelerListener()
      this.addEventBusListener()
    },
    // 添加绑定事件
    addBpmnListener () {
      const that = this
      // 获取a标签dom节点
      const downloadLink = this.$refs.saveDiagram
      const downloadSvgLink = this.$refs.saveSvg
        // 给图绑定事件，当图有发生改变就会触发这个事件
      this.bpmnModeler.on('commandStack.changed', function () {
        that.saveSVG(function(err, svg) {
            that.setEncoded(downloadSvgLink, 'diagram.svg', err ? null : svg)
        })
        that.saveDiagram(function(err, xml) {
            that.setEncoded(downloadLink, 'diagram.bpmn', err ? null : xml)
        })
      })
    },
    addModelerListener() {
      // 监听 modeler
      const bpmnjs = this.bpmnModeler
      const that = this
      // 'shape.removed', 'connect.end', 'connect.move'
      const events = ['shape.added', 'shape.move.end', 'shape.removed']
      events.forEach(function(event) {
        that.bpmnModeler.on(event, e => {
          var elementRegistry = bpmnjs.get('elementRegistry')
          var shape = e.element ? elementRegistry.get(e.element.id) : e.shape
          // console.log(shape)
          if (event === 'shape.added') {
            console.log('新增了shape')
          } else if (event === 'shape.move.end') {
            console.log('移动了shape')
          } else if (event === 'shape.removed') {
            console.log('删除了shape')
          }
        })
      })
    },
    addEventBusListener() {
      // 监听 element
      let that = this
      const eventBus = this.bpmnModeler.get('eventBus')
      const eventTypes = ['element.click', 'element.changed']
      eventTypes.forEach(function(eventType) {
        eventBus.on(eventType, function(e) {
          if (!e || e.element.type == 'bpmn:Process') return
          if (eventType === 'element.changed') {
            that.elementChanged(e)
          } else if (eventType === 'element.click') {
            console.log('点击了element', e.element)
          }
        })
      })
    },
    isInvalid (param) { // 判断是否是无效的值
      return param === null || param === undefined || param === ''
    },
    isSequenceFlow (type) { // 判断是否是线
      return type === 'bpmn:SequenceFlow'
    },
    elementChanged(e) {
      var shape = this.getShape(e.element.id)
      console.log(shape)
      if (!shape) {
        // 若是shape为null则表示删除, 无论是shape还是connect删除都调用此处
        console.log('无效的shape')
        // 上面已经用 shape.removed 检测了shape的删除, 要是删除shape的话这里还会被再触发一次
        console.log('删除了shape和connect')
        return
      }
      if (!this.isInvalid(shape.type)) {
        if (this.isSequenceFlow(shape.type)) {
          console.log('改变了线')
        }
      }
    },
    getShape(id) {
      var elementRegistry = this.bpmnModeler.get('elementRegistry')
      return elementRegistry.get(id)
    },
    // 下载为SVG格式,done是个函数，调用的时候传入的
    saveSVG(done) {
      // 把传入的done再传给bpmn原型的saveSVG函数调用
      this.bpmnModeler.saveSVG(done)
    },
    // 下载为bpmn格式,done是个函数，调用的时候传入的
    saveDiagram(done) {
        // 把传入的done再传给bpmn原型的saveXML函数调用
        this.bpmnModeler.saveXML({ format: true }, function(err, xml) {
            done(err, xml)
        })
    },
     // 当图发生改变的时候会调用这个函数，这个data就是图的xml
    setEncoded(link, name, data) {
      // 把xml转换为URI，下载要用到的
      const encodedData = encodeURIComponent(data)
      // 下载图的具体操作,改变a的属性，className令a标签可点击，href令能下载，download是下载的文件的名字
    //   console.log(link, name, data)
      let xmlFile = new File([data], 'test.bpmn')
    //   console.log(xmlFile)
      if (data) {
        link.className = 'active'
        link.href = 'data:application/bpmn20-xml;charset=UTF-8,' + encodedData
        link.download = name
      }
    }
  },
// 计算属性
  computed: {}
}
</script>

<style scoped>
.containers{
	background-color: #ffffff;
	width: 100%;
	height: calc(100vh - 52px);
}
.canvas{
	width: 100%;
	height: 100%;
}
.panel{
	position: absolute;
	right: 0;
	top: 0;
	width: 300px;
}
.loading {
    font-size: 26px;
}
.containers{
	background-color: #ffffff;
	width: 100%;
	height: calc(100vh - 52px);
}
.canvas{
	width: 100%;
	height: 100%;
}
.panel{
	position: absolute;
	right: 0;
	top: 0;
	width: 300px;
}
.buttons {
    position: absolute;
    left: 20px;
    bottom: 20px;
}
.buttons li {
    display: inline-block;
    margin: 5px;
}
.buttons li a {
    color: #999;
    background: #eee;
    cursor: not-allowed;
    padding: 8px;
    border: 1px solid #ccc;
    text-decoration: none;
}
.buttons li a.active {
    color: #333;
    background: #fff;
    cursor: pointer;
}
</style>